I never really checked anyone else before concluding those are likely just earrings. Harris is too ditzy to try & debate Trump and listen to someone in her ear. She is like a high school girl and has neither the maturity or focus to pull that off.
I hate to say it, but she didn't look horrible in that debate. I am assuming that she really really practiced and got some good coaching. She is also a nervous nelly, so she probably took a sedative or two.